Diatreme is a general term used to describe a volcanic vent or pipe that formed when magma was forced through flat-lying sedimentary rock. The explosive energy of magmas with high dissolved gas contents allowed the magma to be forced through the rocks to form an expanded vent. The sedimentary rock around the vent is lithified (melted together) and small amounts of magma intrude into the rock.

Phreatic eruptions are also associated with diatremes. These steam-driven explosions occur when groundwater is heated by nearby magma, lava or volcanic deposits. The intense and high temperatures of these materials cause water to boil or flash to steam, leading to explosive eruptions of